HUNTSVILLE, Ala.--(BUSINESS WIRE)--ADTRAN®, Inc., (NASDAQ: ADTN), a leading provider of next-generation networking solutions, announced it is delivering on its open interface commitment and decoupling the closed equipment “lock-in” from fiber broadband access solutions. As it unlocks the single-vendor access network, ADTRAN is providing a standards-based carrier-grade set of products and solutions spanning the entire access network from the central office to the cabinet and the customer premise